The field of the present invention is that of aeronautical engines, particularly that of turbomachines.
Aeronautical turbomachines conventionally comprise several modules such as a low-pressure (LP) compressor followed by a high-pressure (HP) compressor, a combustion chamber, a high-pressure turbine followed by a low-pressure turbine, each of which drives the corresponding LP or HP compressor, and a gas ejection device. Each of the turbines is formed alternately of wheels with fixed blades, or guide vanes, and of wheels of moving blades, which together form a turbine stage. The LP turbine modules may comprise several stages, of which there are usually two.
In the remainder of the description, mention of upstream and downstream is to be understood with reference to the direction in which the gases flow through the turbomachine.
The moving blades are carried at their lower part by the rotor of the turbomachine and are fixed to a turbine disk. The guide vane blades are produced in the form of adjacent blade sectors, supported by their upper part and fixed to a casing known as the turbine casing. The moving blades are generally positioned facing an abradable material borne by a circular component fixed to the casing and known as the turbine shroud ring. Small thin ribs borne by the root of the blade, and known as wipers, penetrate this abradable material to ensure sealing between the upstream and downstream sides of the blade, in spite of the deformations resulting from vibration and differing expansions of the various materials.
The turbine shroud rings of the LP stages are produced in the form of several sectors which are each mounted on a rib of the turbine casing, as indicated for example in document FR 96 00241 in the name of the Applicant company, and held in rotation, generally by collaboration between a first stop borne by the shroud ring and a second stop borne either by the guide vane blade sector situated upstream of this sector of the shroud ring or by the casing. In order for the guide vane or casing stop to be able to reach the shroud ring stop, a cutout or recess is made in the shroud ring, and the guide vane or casing stop extends through this cutout or recess.